1. Field of the Invention
This invention relates to a tunnel guide apparatus, in particular a tunnel guide apparatus comprising two bullet members adapted to form two convergent tunnels in a bone, and methods thereof.
2. Description of the Prior Art
In arthroscopy, a common procedure is to replace a damaged ligament with an implant. For example, with reference to FIGS. 1-3, to replace a damaged anterior cruciate ligament (ACL) (11) or a damaged posterior cruciate ligament (PCL) (12) in the knee joint (10), the damaged ligament is removed and the surfaces of the joint cleaned. Thereafter, two tunnels (13, 14) are formed to receive the implant between the condyle of the tibia (15) and condyle of the femur (16).
To form the tunnels (13, 14), a single-tunnel apparatus (18) shown schematically in FIG. 3 may be used. In using this single-tunnel apparatus, the distal tip of a cannulated bullet (19) is pressed against the tibia (15) to determine the direction of the tunnel in the bone. Once the direction is determined, the bullet is locked in place and a guide pin is driven into the bone (15) through a cannula in the bullet (19). Thereafter, the bullet is removed and a drill is threaded on the guide pin to form the tunnel. The implant is inserted in the tunnels (13, 14) between the femur and the tibia, and secured with an internal screw or another mechanism as is known in the art. Similarly, a screw is used to secure the implant in the condyle of the tibia. A method of securing an implant using single tunnels is described in co-pending U.S. patent application Ser. No. 10/822,101, filed Apr. 8, 2004, herein incorporated by reference.
In procedures to replace ACL and PCL ligaments using single tunnels, and with reference to FIG. 3 since the implant is placed in a tunnel (13, 14), the implant assumes the shape of the tunnel, i.e., it is cylindrical. A cylindrical shape having a uniform cross-section however is not the shape of the natural ligament and may be insufficient in controlling the rotational stability of the knee joint.
In a review of single-tunnel/single-bundle ACL reconstructions cited in “Anatomic Double-Bundle ACL Reconstruction: The Restoration of Normal Kinematics”, Dr. F. H. Fu et al. (2005), herein incorporated by reference, patients reported residual instability and pain following single-bundle reconstruction. On the other hand, there are indications that ACL double-bundle reconstruction results in a closer restoration of normal knee kinematics and provides better rotational stability of the knee joint.
Based on these considerations it has been hypothesized that double-bundle ACL reconstruction provides superior restoration of the knee stability and functional outcomes compared to a single-bundle ACL reconstruction. Accordingly, in view of these considerations it is an objective to provide for an apparatus and method to efficiently perform ACL and PCL double-bundle reconstruction.